If a peer reviewer’s comments or recommendations result in major modifications to a Cochrane Review and the has relevant expertise, the Cochrane Review author team may invite the to become a co-author. The invitation must be made after the peer-review process is completed and with the agreement of the existing author team, and the must contribute sufficiently to the Cochrane Review to fulfil Cochrane authorship criteria; otherwise they may be recognised in the Acknowledgements section of the Cochrane Review. Peer reviewers are under no obligation to accept the invitation to become authors.